Answer:
The height of the platform is 20 ft
Step-by-step explanation:
In the figure attached, the problem is shown.
Let's call α to the angle opposite to the 35 ft side. From sine definition:
sin α = opposite/hypotenuse
Taking into consideration both, major and minor triangles:
sin α = 35/(40.5 + 54) = x/54
where x can be isolated, as follows:
x = 35/(40.5 + 54) * 54 = 20 ft
